CVE-2026-64541
In the Linux kernel, the following vulnerability has been resolved: net/smc: fix UAF in smc_cdc_rx_handler() by pinning the socket smc_cdc_rx_handler() looks up the connection by token under the link group's conns_lock, drops the lock, and then dereferences conn and the smc_sock derived from it, ending in sock_hold(&smc->sk) inside smc_cdc_msg_recv(). No reference is held across the lock release. The only reference pinning the socket while the connection is discoverable in the link group is taken in smc_lgr_register_conn() (sock_hold) and dropped in __smc_lgr_unregister_conn() (sock_put), both under conns_lock. Once the handler drops conns_lock, a concurrent close() -> smc_release() -> smc_conn_free() -> smc_lgr_unregister_conn() can drop that reference and free the smc_sock, so the handler's later sock_hold() runs on freed memory: WARNING: lib/refcount.c:25 at refcount_warn_saturate Workqueue: rxe_wq do_work refcount_warn_saturate (lib/refcount.c:25) smc_cdc_msg_recv (net/smc/smc_cdc.c:430) smc_cdc_rx_handler (net/smc/smc_cdc.c:502) smc_wr_rx_tasklet_fn (net/smc/smc_wr.c:445) tasklet_action_common (kernel/softirq.c:938) handle_softirqs (kernel/softirq.c:6
No public exploitation has been reported so far. No distribution fix is listed yet; apply vendor mitigations and monitor.
Recommended action: Track your distribution's security tracker and apply the fix as soon as it ships.
Affected & fixed versions by distribution
Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.
No affected package in the tracked watchlist yet (Debian, Ubuntu, Arch, SUSE, Red Hat...). Triage may still be pending.